I'm trying to tell the difference between a string value and an integer value -- not a string type variable and an integer type variable. I.e., if a string type variable contains the value "503", I want to consider it an integer. So, I use intval(), figuring that if the intval() of a variable is the same as the value of the variable, then the variable has an integer value.

For example, if $x = "503", then intval($x) = 503. So, $x == intval($x) and I consider it an integer. If $x = "this is a test", then intval($x) is 0. Since $x != intval($x), I don't consider it an integer. Here's the part I don't understand:

<?
$x = "this is a test";
echo "<p>\$x = " . $x;
echo "<p>intval(\$x) = " . intval($x);
if ($x == intval($x)) {
  echo "<p>\$x is an int";
}
?>

The output of this script is:

$x = this is a test
intval($x) = 0
$x is an int

How the heck is $x == intval($x) if $x = "this is a test" and intval($x) = 0?